For an EV (Electric Vehicle) hardshell battery, in order to avoid overcharging, a solution widely adopted in the related industry is to cut off a main circuit of the battery before failure of a battery cell to prevent the battery from being charged continuously and thus ensure the battery's safety. A conventional configuration is as follows: a current cut-off structure is provided in the main circuit connecting a first terminal and an electrode component, and a second terminal is always insulated from the current cut-off structure; when the battery is being overcharged, gas is produced inside the battery, and if the internal pressure is increased to a certain value, the current cut-off structure will be activated to cut off the connection between the first terminal and the electrode component and prevent the battery from being charged continuously. However, when the battery is under a nail penetration test, namely, when a metal nail penetrates a case or a cap plate of the battery, the penetration position will be severely heated and even spark, which may make the battery out of control and cause fire or explosion.
In the current cut-off structure, a turnable plate is attached to a connecting plate, but the turnable plate is electrically connected to the cap plate directly. Extra resistance elements cannot be added on the cap plate of the battery having such a current cut-off structure. Thus, the battery may not pass the nail penetration test.